Removes no longer needed parentheses in @Composable() annotations

-Enables the NonParenthesizedAnnotationsOnFunctionalTypes flag to disable the IDE warning
-Temporarily disables the 'paren-spacing' lint in ktlint, due to: https://github.com/pinterest/ktlint/issues/737
-Turns unnecessary parentheses into a 'warning', and stops ignoring this IDE inspection in the UI project

Bug: b/155391691
Test: ./gradlew bOS, Studio
Change-Id: Ib4af53591b82a0d56ae0733ff2561196c2d49635

diff --git a/ui/ui-foundation/integration-tests/foundation-demos/src/main/java/androidx/ui/foundation/demos/ListDemos.kt b/ui/ui-foundation/integration-tests/foundation-demos/src/main/java/androidx/ui/foundation/demos/ListDemos.kt
index b3082ec..c1d73bc 100644
--- a/ui/ui-foundation/integration-tests/foundation-demos/src/main/java/androidx/ui/foundation/demos/ListDemos.kt
+++ b/ui/ui-foundation/integration-tests/foundation-demos/src/main/java/androidx/ui/foundation/demos/ListDemos.kt

@@ -82,7 +82,7 @@
 }
 
 @Composable
-fun Button(modifier: Modifier, onClick: () -> Unit, children: @Composable() () -> Unit) {
+fun Button(modifier: Modifier, onClick: () -> Unit, children: @Composable () -> Unit) {
     Clickable( {
         Box(
             modifier = modifier,

diff --git a/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/DraggableTest.kt b/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/DraggableTest.kt
index db92c21..e324658 100644
--- a/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/DraggableTest.kt
+++ b/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/DraggableTest.kt

@@ -423,7 +423,7 @@
         }
     }
 
-    private fun setDraggableContent(draggableFactory: @Composable() () -> Modifier) {
+    private fun setDraggableContent(draggableFactory: @Composable () -> Modifier) {
         composeTestRule.setContent {
             Stack {
                 val draggable = draggableFactory()

diff --git a/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/ScrollableTest.kt b/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/ScrollableTest.kt
index 91ef177..27dfc12 100644
--- a/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/ScrollableTest.kt
+++ b/ui/ui-foundation/src/androidTest/java/androidx/ui/foundation/ScrollableTest.kt

@@ -572,7 +572,7 @@
         }
     }
 
-    private fun setScrollableContent(scrollableModifierFactory: @Composable() () -> Modifier) {
+    private fun setScrollableContent(scrollableModifierFactory: @Composable () -> Modifier) {
         composeTestRule.setContent {
             Stack {
                 val scrollable = scrollableModifierFactory()

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/AdapterList.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/AdapterList.kt
index 351344c..42934f8 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/AdapterList.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/AdapterList.kt

@@ -64,7 +64,7 @@
 
 private class ListState<T> {
     lateinit var recomposer: Recomposer
-    lateinit var itemCallback: @Composable() (T) -> Unit
+    lateinit var itemCallback: @Composable (T) -> Unit
     lateinit var data: List<T>
 
     var forceRecompose = false
@@ -513,7 +513,7 @@
 fun <T> AdapterList(
     data: List<T>,
     modifier: Modifier = Modifier,
-    itemCallback: @Composable() (T) -> Unit
+    itemCallback: @Composable (T) -> Unit
 ) {
     val state = remember { ListState<T>() }
     state.recomposer = currentComposer.recomposer

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Box.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Box.kt
index 62b3fcb..14508cc 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Box.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Box.kt

@@ -77,7 +77,7 @@
     paddingEnd: Dp = Dp.Unspecified,
     paddingBottom: Dp = Dp.Unspecified,
     gravity: ContentGravity = ContentGravity.TopStart,
-    children: @Composable() () -> Unit = emptyContent()
+    children: @Composable () -> Unit = emptyContent()
 ) {
     val borderModifier =
         if (border != null) Modifier.drawBorder(border, shape) else Modifier

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
index 95b4e25..59fe9002 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Clickable.kt

@@ -60,7 +60,7 @@
     enabled: Boolean = true,
     onClickLabel: String? = null,
     interactionState: InteractionState? = null,
-    children: @Composable() () -> Unit
+    children: @Composable () -> Unit
 ) {
     Semantics(
         container = true,

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/DeterminateProgressIndicator.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/DeterminateProgressIndicator.kt
index a4744cd..c459dfe 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/DeterminateProgressIndicator.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/DeterminateProgressIndicator.kt

@@ -38,7 +38,7 @@
 @Composable
 fun DeterminateProgressIndicator(
     @FloatRange(from = 0.0, to = 1.0) progress: Float,
-    children: @Composable() () -> Unit
+    children: @Composable () -> Unit
 ) {
     if (progress !in 0f..1f) {
         throw IllegalArgumentException("Progress must be between 0.0 and 1.0")

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
index 697dec6..06a1553 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Dialog.kt

@@ -48,7 +48,7 @@
  * @param children The content to be displayed inside the dialog.
  */
 @Composable
-fun Dialog(onCloseRequest: () -> Unit, children: @Composable() () -> Unit) {
+fun Dialog(onCloseRequest: () -> Unit, children: @Composable () -> Unit) {
     val context = ContextAmbient.current
 
     val recomposer = currentComposer.recomposer
@@ -87,7 +87,7 @@
         setContentView(frameLayout)
     }
 
-    fun setContent(children: @Composable() () -> Unit) {
+    fun setContent(children: @Composable () -> Unit) {
         // TODO: This should probably create a child composition of the original
         composition = frameLayout.setContent(recomposer, children)
     }

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
index fe81619..c569616 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Scroller.kt

@@ -207,7 +207,7 @@
     scrollerPosition: ScrollerPosition = ScrollerPosition(),
     modifier: Modifier = Modifier,
     isScrollable: Boolean = true,
-    child: @Composable() () -> Unit
+    child: @Composable () -> Unit
 ) {
     Scroller(scrollerPosition, modifier, true, isScrollable, child)
 }
@@ -237,7 +237,7 @@
     scrollerPosition: ScrollerPosition = ScrollerPosition(),
     modifier: Modifier = Modifier,
     isScrollable: Boolean = true,
-    child: @Composable() () -> Unit
+    child: @Composable () -> Unit
 ) {
     Scroller(scrollerPosition, modifier, false, isScrollable, child)
 }
@@ -248,7 +248,7 @@
     modifier: Modifier,
     isVertical: Boolean,
     isScrollable: Boolean,
-    child: @Composable() () -> Unit
+    child: @Composable () -> Unit
 ) {
     val direction =
         if (isVertical) DragDirection.Vertical else DragDirection.Horizontal
@@ -282,7 +282,7 @@
     scrollerPosition: ScrollerPosition,
     modifier: Modifier,
     isVertical: Boolean,
-    child: @Composable() () -> Unit
+    child: @Composable () -> Unit
 ) {
     Layout(
         modifier = modifier.clipToBounds(),

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Text.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Text.kt
index a06b87c..8d09b84 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/Text.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/Text.kt

@@ -217,7 +217,7 @@
  * styled explicitly.
  */
 @Composable
-fun ProvideTextStyle(value: TextStyle, children: @Composable() () -> Unit) {
+fun ProvideTextStyle(value: TextStyle, children: @Composable () -> Unit) {
     val mergedStyle = currentTextStyle().merge(value)
     Providers(TextStyleAmbient provides mergedStyle, children = children)
 }

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/MutuallyExclusiveSetItem.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/MutuallyExclusiveSetItem.kt
index cdc3d5b..fb96bc9 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/MutuallyExclusiveSetItem.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/MutuallyExclusiveSetItem.kt

@@ -44,7 +44,7 @@
     selected: Boolean,
     onClick: () -> Unit,
     modifier: Modifier = Modifier,
-    children: @Composable() () -> Unit
+    children: @Composable () -> Unit
 ) {
     // TODO: when semantics can be merged, we should make this use Clickable internally rather
     //  than duplicating logic

diff --git a/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt b/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
index d179f52..074ac96 100644
--- a/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt
+++ b/ui/ui-foundation/src/main/java/androidx/ui/foundation/selection/Toggleable.kt

@@ -53,7 +53,7 @@
     onValueChange: (Boolean) -> Unit,
     enabled: Boolean = true,
     modifier: Modifier = Modifier,
-    children: @Composable() () -> Unit
+    children: @Composable () -> Unit
 ) {
     TriStateToggleable(
         state = ToggleableState(value),
@@ -91,7 +91,7 @@
     onClick: () -> Unit,
     enabled: Boolean = true,
     modifier: Modifier = Modifier,
-    children: @Composable() () -> Unit
+    children: @Composable () -> Unit
 ) {
     // TODO(pavlis): Handle multiple states for Semantics
     Semantics(container = true, properties = {